I run the code by copying the code from the browser window into the interactive Ocaml REPL (Read Eval Print Loop). Most of the pages need an extra new-line at the end.

Constituents for the tests:
the codeRespective notesrequires:Description
LinearnotesSome matrix routines
sort, cross, rp sort note
toolsmiscellaneous print routines
gluenotessortconnecting zones to their neighbors
zonenotestools; Linearlogic of geodesics and curvature from inside a zone
Jignoteszone; sort; crossGeneral logic for embedding
ji32belowJig; rp; glue Geodesic thru 2 tetrahedra embedded in 3D
ji24belowJig; rp; glueGeodesic thru 4 triangles embedded in 2D
ji21 (curve)belowJig; rp; glueBone probe in 1 triangle embedded in 2D
ji31 (curve)belowJig; rp; glueBone probe in 1 tetrahedron embedded in 3D
Jognoteszone; sortExplicit metric in place of metric from embedding space.
jo24notesJog; glueGeodesic over surface of regular tetrahedron, consisting of 4 triangles
jo44noteJog; glueAll the way round a bone in 4D; 4 regular 4 simplexes
jo44fnoteJog; glueAll the way round a boneā€”flat by construction; 4 nearly regular 4 simplexes.
mxlsource of consistent noise
jo44fdnoteJog; glue; mxlElaboration on above: adding random noise to edge lengths
jo44fdxnoteJog; glueElaboration on above: allowance for individual fiddling with edge lengths
jo43noteJog; glueAll the way round a bone in 4D

A minimal demo of a ray crossing between two tetrahedra embedded in 3D. top is the topology, embd is the embedding in 3D.
Four triangles about the origin. The first vertex was originally at (0, 0) but (-.1, .6) is a much stronger test as it makes the geodesic traverse all four triangles and with more general zone shapes.
One embedded triangle, curve probe introduced on facet 2, mentioning bone at (0., 0.) by naming facet vertex opposite that bone.
A single tetrahedron whose dihedral angle we measure.